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Who made the the biggest SCT ever? Celestron?

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110 replies to this topic

#51 Martin Lyons

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Posted 11 July 2016 - 11:52 PM

 

Wow, I liked that Meade 20" story and am glad they made it so well. I too, wonder how many of those monsters were made (or the C-22's).

My C-11 on a DX mount is a monster, I can't imagine what it takes to lift 200 pounds onto a dovetail seven feet in the air. Ha! A crane.

Clear skies,
Peter

 

They need to supply a hoist (like an engine hoist) with the telescope!  One-man setup, with enough tools!

 

Something like this?

 

Telescope crane2.jpg


Edited by Martin Lyons, 11 July 2016 - 11:52 PM.

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#52 Rick Woods

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Posted 12 July 2016 - 12:04 AM

What a great, informative thread! :D


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#53 dothead

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Posted 12 July 2016 - 04:20 AM

No, we have a bigger one here in Germany:

 

http://www.tls-taute...index.php?id=51

 

Clear skies to you,

 

Ralph


Edited by dothead, 12 July 2016 - 04:24 AM.


#54 kennyrichmond

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Posted 12 July 2016 - 07:26 AM

Meade is back in the 20" ACF and MaxMount II business: https://telescopes.n...unt-tripod.html

 

Mine, now sold, had Pyrex glass that is no longer available from Corning.  The MaxMount now comes with Starlock and is the same price I paid in 2007.

 

Ken R.



#55 GJJim

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Posted 12 July 2016 - 08:40 AM

Meade is back in the 20" ACF and MaxMount II business: https://telescopes.n...unt-tripod.html

 

Mine, now sold, had Pyrex glass that is no longer available from Corning.  The MaxMount now comes with Starlock and is the same price I paid in 2007.

 

Ken R.

Ken, on the scope you owned, did you ever get a look at the method Meade used to support that heavy chunk of glass? I'm curious because one of my projects is converting an older 14" LX200 to a open tube, fixed primary configuration. Meade hinted in the literature that the fixed primaries were supported from the back versus the central column mounting used in the moving mirror scopes.



#56 garret

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Posted 12 July 2016 - 08:49 AM

 

That is a Schmidt, not a Schmidt-Cassegrain

for Meade this is a Schmidt-Cassegrain :grin: (Advanced RC, ACF or whatever...)

Garret



#57 rmollise

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Posted 12 July 2016 - 12:00 PM

 

That is the Oschin Scmidt camera. It's not an SCT and you cannot use if visually, either.



#58 rmollise

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Posted 12 July 2016 - 12:00 PM

 

 

Do any of these scopes ever need to be recoated?

Can you remove both mirrors of the 22" Celestron and other big SCT for a recoat? 

 

Garret

 

 

 

Yes. Easy? No.


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#59 TCW

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Posted 12 July 2016 - 02:47 PM

Meade is back in the 20" ACF and MaxMount II business: https://telescopes.n...unt-tripod.html

 

Mine, now sold, had Pyrex glass that is no longer available from Corning.  The MaxMount now comes with Starlock and is the same price I paid in 2007.

 

Ken R.

I had a chat with customer service and they say that Meade is building 5 of the 20" scopes for sale by the end of the year.  The specs say that the primary mirror will be Borosilicate.

 

The story of why you sold your scope and how it performed would be interesting,


Edited by TCW, 12 July 2016 - 02:57 PM.


#60 kennyrichmond

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Posted 12 July 2016 - 07:55 PM

GJJim,

 

I don't know how the primary was fixed to the tube on the 20" Meade, but there was no movement because the corrector moved in and out on 3 encoded threaded rods for focus.

 

TCW

My experience with the scope and Meade was very positive and has been the subject of several threads here since I acquired it.  Except for one year when it went unused in a Wellsboro, PA observatory due to drilling burn-off and illuminated browned skies, the scope traveled extensively; three times back to Meade for mount upgrades, and many star parties.  In 2013, it returned from Meade the last time, just before the company's change in ownership.  It had been sold for drop shipment delivery from Meade to a French institution in Polynesia.  The buyer ultimately defaulted and walked away from a 6 figure deposit.  So it returned to me and after a year engaged in a mild international legal dispute, I uncrated it then did a five month expedition with it West of the Dakotas.   I used it visually with the Denkmier LOA's while 2 or 3 other triplets were hanging on the Max Mount using machined brackets equipped with various DSLRs and a QSI 683.  

 

With either 13 or 21 mm Ethos oculars, the views remain unmatched by any of the many scopes that I've peered through or owned. Twenty inches at f/8 shows color on the best of nights at resolutions that truly "put you there".  The ACF (RCX) optics are superb with pin point stars and contrast that seems to make filaments glow against an inky background.  One needn't twist a focuser back and forth trying to pinch out just a little, itsy....bitsy... more....detail.  With this scope the resolution suddenly explodes on one's consciousness at 300X sucking your breath away.  The full travel of the corrector plate is about an inch and a quarter.  I hung a 3" Optec TCF on the back to take the load off the main focuser out of fear when Meade changed hands.

 

So why was it sold again?  Well, a scope of this heft and dimension demands the fairest, darkest skies.  I can say that in nine years of use I encountered 15 perfect nights with it - just enough to fuel an intractable obsession.  The equipment to transport it behind the front sometimes 750 miles in a day, and live with it far from civilization for weeks, more than doubled the cost of the scope. Even with hydraulics (and my rather brutish physical development) , the scope does become challenging to erect alone in the wilderness for one of 70 years.  My grown children have threatened to leave my body rot in a desert until I started bringing Finnegan the dog with me. (They want to get him and the diesel truck back)

 

So today I'm left with a 14" Celestron Fastar that, with the LOA's, does provide a modest bit of consolation, but I won't test it on the most extended subjects lest I start mourning.

 

Ken


Edited by kennyrichmond, 12 July 2016 - 08:17 PM.

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#61 Phil Barker

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Posted 12 July 2016 - 09:42 PM

having spent many a night using an excellent 16 inch rcx f8 I would love to buy a 20 one day and set up in a decent observatory.

the 16 is in a roll off roof at Canterbury astronomical societies west melton rf joyce observatory and gets used most clear nights.

in a nearby dome is a vintage classical cassegrain of 14.3 inch f-17 and the meade is clearly better all round.

#62 gnabgib

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Posted 12 July 2016 - 10:08 PM

If i remember correctly Jim Riffle of Astro Works produced at least two 24.5 inch schmidt cassegrains in the late eighties! 



#63 skywatcher3000

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Posted 13 July 2016 - 01:32 AM

I believe you're mixing up Jim Riffle for Bill Anderson. I wrote earlier in this thread about how my optician friend, Bill Anderson, started to make a couple of 24" SCT systems back in the eighties, but the project was cancelled and they were never finished. I don't think that Jim ever got involved with Schmidts, as he said that he would leave those to Bill Anderson to make (if memory serves correctly)!!



#64 gnabgib

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Posted 13 July 2016 - 07:10 AM

I believe you're mixing up Jim Riffle for Bill Anderson. I wrote earlier in this thread about how my optician friend, Bill Anderson, started to make a couple of 24" SCT systems back in the eighties, but the project was cancelled and they were never finished. I don't think that Jim ever got involved with Schmidts, as he said that he would leave those to Bill Anderson to make (if memory serves correctly)!!

You could be correct.  I was looking at Jim Riffle's web page and it mentioned he made various telescopes including 24.5 inch f/6.2 schmidt cassegrains. 


Edited by gnabgib, 13 July 2016 - 07:10 AM.

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#65 rab1701a

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Posted 01 December 2016 - 09:57 PM

a recall an article about one a few years back used as a university scope. Not sure where it was.

the finderscope is probably a c8

I don't know if this is the one your talking about but the Colorado State University Pueblo has one. 22" Celestron.  My club has access to it. Need's some work and upgrades but still working.


Edited by rab1701a, 01 December 2016 - 10:15 PM.

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#66 stevecoe

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Posted 07 December 2016 - 03:30 AM

Howdy all;

 

Here is a shot of me with the Meade 20 inch at Riverside in 2007.  The views in it were very poor.  There was no point of good focus.  I was very disappointed, particularly by a scope they would bring to a big conference.

 

Too bad

Steve Coe

 

Steve_Meade_20.jpg



#67 rmollise

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Posted 07 December 2016 - 08:40 AM

Howdy all;

 

Here is a shot of me with the Meade 20 inch at Riverside in 2007.  The views in it were very poor.  There was no point of good focus.  I was very disappointed, particularly by a scope they would bring to a big conference.

 

Too bad

Steve Coe

 

attachicon.gifSteve_Meade_20.jpg

 

Chances are its optics were fine. Big, huge, SCT sitting in the Sun all day is not a recipe for good images after sundown. ;)


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#68 StarMike8SE

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Posted 08 December 2016 - 03:42 PM

I found this old pic of the Celestron C22

 

0066596_bob-piekiel-and-celestron-c22b.jpg


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#69 MrG

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Posted 08 December 2016 - 04:18 PM

Having owned a C14 and worried plenty over that giant delicate(?) corrector plate, I think one any bigger would cause me to have a breakdown.

 

G



#70 skywatcher3000

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Posted 08 December 2016 - 06:23 PM

Hey Mike where did you find that photo of the C22, I never saw that in any of my stuff from Celestron that I collected over the years, as well as from any articles on it!! The corrector for the C22 was very thick (relatively speaking) and could easily take accidental abuse to the scope. I know, you're going to ask me just how thick it was, but I can't put my hands on the data right at the moment!! The corrector and the primary mirror were thick enough to take a VERY LONG time to cool down, from personal use. I know that some of these scopes that were installed in professional observatories had air conditioning systems to keep the scope cool throughout the day, so that the scope was at ambient outdoor temperatures at nightfall, ready to use!!


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#71 xHarry

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Posted 09 December 2016 - 04:21 AM

The biggest Schmidt-cassegrain telescope is the 2-meter (1.34 meter free aperture) Alfred Jensch Telescope at the Karl Schwarzchild Observatory in Tautenburg, Germany.

 

http://www.tls-taute...x.php?id=51&L=1

 

It's more of a Schmidt camera with additional Nasmyth and coudé foci, than a true SCT, but I'd say it counts anyway.

 

 

Clear skies!

Thomas, Denmark

https://en.wikipedia...schin_telescope is this number 2?



#72 StarMike8SE

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Posted 09 December 2016 - 09:22 AM

Hey Mike where did you find that photo of the C22, I never saw that in any of my stuff from Celestron that I collected over the years, as well as from any articles on it!! The corrector for the C22 was very thick (relatively speaking) and could easily take accidental abuse to the scope. I know, you're going to ask me just how thick it was, but I can't put my hands on the data right at the moment!! The corrector and the primary mirror were thick enough to take a VERY LONG time to cool down, from personal use. I know that some of these scopes that were installed in professional observatories had air conditioning systems to keep the scope cool throughout the day, so that the scope was at ambient outdoor temperatures at nightfall, ready to use!!

Sorry, I have had that pic for a long time, so don't remember where I got it.  I bet it was a beast to set up



#73 junomike

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Posted 09 December 2016 - 12:54 PM

buytelescopes.com  (Anacortes)

 

Also, found this Ad from 1968 showing the C22 listed at $29,500!

Using the US  Inflation Calculator that works out to $205,000 today! :shocked:

 

I wouldn't expect they'd sell many of them today at that price.

 

Mike



#74 p51son

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Posted 09 December 2016 - 04:28 PM

https://www.buyteles...ery/photo/66596

 

http://night-watch.o..._Telescope.html

 

https://www.buyteles...ery/photo/66596



#75 skywatcher3000

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Posted 10 December 2016 - 01:34 AM

Thanks junomike and p51son for those links!!




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